SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934

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Filed by a Party other than the Registrant ý

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o   Definitive Proxy Statement
ý   Definitive Additional Materials
o   Soliciting Material Pursuant to §240.14a-12

Quanta Services, Inc.

(Name of Registrant as Specified In Its Charter)

Aquila, Inc. (f/k/a Utilicorp United Inc.)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)
         
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Explanatory Note

        Aquila, Inc. (formerly known as UtiliCorp United Inc.), a Delaware Corporation, is filing the materials contained in this Schedule 14A with the Securities and Exchange Commission on May 3, 2002 with respect to the solicitation of proxies for electing nominees to the board of directors of Quanta Services, Inc. ("Quanta") at the 2002 annual meeting of stockholders of Quanta.

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News Release

Media Contacts:
Judith Wilkinson / Eden Abrahams
Joele Frank, Wilkinson Brimmer Katcher — (212) 355-4449
  Investor Contact:
Ellen Fairchild
Aquila — (816) 527-1409

AQUILA MAILS ADDITIONAL PROXY MATERIALS TO
QUANTA STOCKHOLDERS

        Kansas City, MO, May 3, 2002 — Aquila, Inc. (NYSE: ILA; formerly UtiliCorp United Inc.) announced today that it is mailing additional proxy materials to Quanta stockholders of record for the upcoming Annual Meeting scheduled for May 23, 2002, in support of Aquila's slate of nominees for election to Quanta's 2002 Board of Directors. Included in Aquila's materials is the following letter to Quanta stockholders:

LETTERHEAD

To Our Fellow Quanta Stockholders:

        Accompanying this letter are Aquila's proxy statement and a GOLD proxy card relating to the upcoming 2002 annual meeting of stockholders of Quanta Services, Inc. to be held on May 23, 2002. This material is being sent to all Quanta stockholders entitled to vote at its annual meeting. We are seeking your support to elect a new board of directors. For the reasons discussed in this letter and the accompanying proxy statement, we urge you to sign and return the enclosed GOLD proxy card in support of Aquila's board nominees.

AQUILA IS COMMITTED TO MAXIMIZING VALUE FOR ALL QUANTA STOCKHOLDERS

        Aquila is Quanta's largest stockholder with a total equity investment exceeding $715 million. Consequently, our interest is closely aligned with all other Quanta stockholders and we only stand to gain from our investment in Quanta when and if Quanta's share price increases, as is true for every other stockholder. However, we realize that in order to win your support we need to provide our fellow stockholders with a compelling program for restoring value at Quanta. Together with our financial advisor, Salomon Smith Barney Inc., we have been evaluating a full range of options for maximizing stockholder value. Please consider what we are offering you:


We believe that our economic program offers significantly greater opportunities to enhance value at Quanta than the current Board's status quo posture can hope to achieve.

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WE BELIEVE IT IS IMPOSSIBLE FOR MANAGEMENT TO ARGUE THAT THEIR RECENT ACTIONS ARE IN THE BEST INTEREST OF STOCKHOLDERS

        You should know that the Board has taken actions that prohibit Aquila from buying shares from fellow stockholders. Apparently, Quanta's directors had no complaints so long as they were the ones who sold their shares to Aquila and pocketed millions. In fact, during 1999 and 2000, Aquila purchased shares of Quanta stock from members of Quanta's Board and senior management for an aggregate price exceeding $115 MILLION:

Individuals Selling
Stock to Aquila

  Position with Quanta
  Value Received
from Aquila

John R. Colson   CEO and Director   $ 40,149,375
Vincent D. Foster   Chairman and Director     7,647,500
John R. Wilson   SVP and Director     20,211,937
John A. Martell   Former Director     12,327,500
Gary A. Tucci   Director     24,471,250
Luke T. Spalj   Senior Vice President     9,559,375
James H. Haddox   Chief Financial Officer     2,188,312
       
    TOTAL   $ 116,555,249
       

        Yet, once they sold their shares to Aquila, the directors took it upon themselves to try to maintain control by adopting an amendment to Quanta's Poison Pill—in violation, we believe, of Quanta's expressed contractual commitments to Aquila—that limited Aquila's ability to buy more shares from other stockholders. If Quanta's directors and management have essentially bailed out of their investment in Quanta, why won't they let Aquila purchase your shares? We believe that the directors and management, now that they have disposed of such a large portion of their shares, are trying to further enrich themselves, as well as to hold onto their jobs, by adopting the Stock Employee Compensation Trust, or SECT, and lucrative change-of-control agreements—all at your expense. Consider the following:

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        The self-serving actions of Quanta's Board and management will have consequences:

QUANTA'S DIRECTORS HAVE BROKEN IMPORTANT AGREEMENTS
IN ORDER TO RETAIN CONTROL

        As an important inducement to Aquila making its initial investment in Quanta, the Quanta board of directors agreed that Aquila would be permitted to continue to purchase up to 49.9% of Quanta's fully diluted shares without interference from Quanta. What's more, Quanta agreed to assist Aquila in its efforts to acquire additional Quanta shares. Aquila would not have made any investment in Quanta without these promises. These agreements were memorialized by the following contractual provisions:

        Remarkably, after the members of the current Quanta board sold their shares to Aquila, they took it upon themselves to try to hold onto control of Quanta by adopting an amendment to Quanta's Poison Pill that reduced the threshold at which Aquila is permitted to own Quanta stock to 39%, approximately our current level of ownership. This obvious breach of contract has prevented Aquila from buying your stock and is the subject of an arbitration preceding that could result in Quanta owing Aquila significant monetary damages.

WE BELIEVE THE BEST COURSE FOR RESTORING VALUE AT QUANTA IS FOR STOCKHOLDERS TO SUPPORT AQUILA'S NOMINEES FOR ELECTION TO THE BOARD

        We do not believe it is in your best interest as a stockholder of Quanta to vote in favor of continuing the status quo. We firmly believe it is in the best interests of Quanta and its stockholders for you to vote in favor of our nominees and, accordingly, we urge you to sign and return Aquila's GOLD proxy card and discard Quanta's white proxy card.

  On Behalf of Aquila, Inc.

 

SIGNATURE
  Robert K. Green
President and Chief Executive Officer
May 3, 2002  

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